Dell Latitude E6510 with latest BIOS (A09) installed has an issue where the keyboard (both internal and USB) will stop accepting inputs as soon as the MEBx option is chosen during start up. Keyboard works in normal BIOS menu.
Hi Steven, I talked your question over with the Manageablilty and Security team and they seem to think that this is an issue to raise with Dell.
This may or may not relate: I bought a desktop system for our lab herefrom Dell last year and when I received it I could get into the MEBx menu, but I believe that my keyboard wouldn't work after that..very similar to what you are describing. Eventually we discovered that although I had requested a vPro enabled machine, I received one that was not vPro enabled.
I don't know if this is the same issue as yours, but talking to Dell should at least give you some additional information.
What is interesting is that keyboard control in the MEBx menu worked last month. I was able to configure the MEBx initially and haveno problems accessing the laptop through the AMT. I will raise this issue with Dell.